Given that nearly half of American marriages end in divorce, there’s a large secondhand market for diamonds. But is snapping up someone else’s breakup bauble—or stone—a good bargain or bad juju?

You can certainly save a considerable sum by buying used jewelry. For example, the best prices we found for the one-carat mined stone we sought were around $7,500 for a “new” one; we found a nearly identical one at TheRealReal.com for $3,250.

That such savings are available on the secondhand market deflates the argument often made by mined-diamond merchants who promise their stones will hold their resale value better than those grown in labs; they probably will, but not significantly better. Our specified 1.5-carat lab-grown stone typically cost $3,000 and up among retailers we shopped; we found similar ones on secondhand sites for less than $1,500.

For buyers, sources of secondhand diamonds include Craigslist, eBay, Etsy, TheRealReal, jewelry stores that sell vintage rings, and, for the practical-if-not-romantic, pawn shops. When shopping for diamond jewelry, we found these online sites incredibly difficult to navigate and sellers’ descriptions often lacking important details. If you choose to bargain hunt this way, get a GIA-certified diamond and seek a return window that allows you enough time to get your purchase appraised.

Keep in mind when shopping that if you don’t like the setting, you can easily have it reset to your liking and still save a lot over buying retail.

Since the GIA didn’t start issuing reports until 1953, diamonds in vintage settings may be hard to evaluate. If you want the retro, often one-of-a-kind appeal of an antique piece, shop at stores that have highly regarded estate or vintage jewelry departments—and staffers who know about older cuts like mine and rose. You’ll sometimes score a deal on a vintage ring or stone, but not always; a particularly artful setting or unusually cut stone could mean a flash-from-the-past is priced the same (or more) than a current bijou.

If you go with person-to-person purchasing (eBay, Etsy, or Craigslist), beware of scams like a phony GIA certificate, defective diamonds that have been treated, and more. Paying via PayPal or with a credit card will let you dispute the charge if you buy from a diamond-biz deplorable.

If you want to sell a stone, don’t expect to get what you paid for it. DiamondBuyersIntl.com offered our shoppers $6,060 to $9,090 for a 1.5-carat, H color, VS2 stone, which is about half its retail price. (This is another indication that mined diamonds don’t really hold their value very well.)

You might get a higher price selling via eBay or Craigslist rather than at a store, but you’ll get your cash faster from a jewelry store or mail-in gem buyer, and avoid the hassle of setting up your online sale, weeding out weirdos, etc. Online, major players include DiamondBuyersIntl.com and WPDiamonds.com. There’s also a kind of middleman business, IDoNowIDont.com, which helps you sell your old diamond or ring. It takes 15 percent of the sales price as commission.

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